Electrolysis

• What is the aim of the electrolysis experiment?

  Investigate electrolysis of aqueous solutions
• What equipment is needed for the electrolysis experiment?

  • 0.5 M copper(II) chloride solution
  • 0.5 M sodium chloride solution
  • Petri dish lid with bored holes
  • Two carbon rod electrodes with support bungs
  • Two crocodile/4mm plug leads
  • Low voltage power supply
  • Blue litmus paper
  • Forceps
• Why is it important that the electrodes do not touch during the experiment?

  To prevent short-circuiting of the power supply
• What should you do after adding copper chloride solution to the beaker?

  Add the lid and insert electrodes
• What voltage should the power supply be set to during the experiment?

  4V
• What is the purpose of holding litmus paper near the positive electrode?

  To observe any color change indicating reaction
• What should be observed at the negative electrode after turning off the power supply?

  Record observations at the electrodes
• What are the steps for repeating the experiment with sodium chloride?

  1. Add 50cm​3​ of sodium chloride solution to a beaker.
  2. Add the lid and insert electrodes through the holes.
  3. Attach crocodile leads to the electrodes.
  4. Set the power supply to 4V and switch it on.
  5. Hold litmus paper near the positive electrode.
  6. Turn off the power supply after a few minutes.
  7. Observe the negative electrode for effervescence.
• What should be observed at the negative electrode during the sodium chloride experiment?

  There should be effervescence
• What safety precautions must be taken during the experiment?

  • Wear safety goggles
  • Ensure the room is well ventilated
  • Chlorine gas is toxic
• Why must safety goggles be worn during the experiment?

  To protect eyes from harmful substances
• Why should the room be well ventilated during the experiment?

  To disperse toxic chlorine gas produced
• What are the key differences in observations between copper(II) chloride and sodium chloride during electrolysis?

  • Copper(II) chloride: Observe color change at electrodes
  • Sodium chloride: Observe effervescence at negative electrode